Screw propeller



May 22, 1923.

H. LElTN ER SCREW PROPELLER Filed March 25 1919 Patented May 22, 192s.

r T Pics.

SCREW IPROPELLEE.

Application filed March 25, 1919. Serial No. 285,069.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

chiefly designed for use on air-craft, and to that class of propeller in which the blades are hollow, and are composed of separate sheet metal plates welded or otherwise suitably joined together at the edges.

The object of my invention is to improve the construction of propellers of this type,

and to this end I form two or more blades of a propeller together, by rolling, stamping, or otherwise shaping to the required thickness and form a pair of sheet metal plates, each plate forming the front surface of one blade and the rear surface of an adjacent blade. In general it will be advantageous to form the blades in pairs as for a two-bladed propeller, but it is obvious that propellers having more than two blades may be formed in a similar manner. lhe plates which form a pair of blades are'shaped at the centre so as to enclose either wholly or partially a convenient form of hub or boss, as, for example, a tubular or a spool-shaped hub. To the sides of this hub a pair of plates shaped as above described are securely fixed by welding, soldering or other suitable means, and the edges of the said plates are then welded or soldered together all around, and finished off by grinding or otherwise.

Such propeller blades may be supported or strengthened internally by any suitable or special means, such, for example, as those described in my Patent No. 1,328,005 dated Jan. 13, 1920.

It will be understood that there are two such shaped plates for each pair of blades, one for the front face of one blade and the rear face of the other blade, and one for the rear face of the first blade and the front face of the second blade. After these have been put together, and their edges suitably united, the remainder of the hub portion may be covered or filled in with thin sheet ever, in any way reqiured for the purpose of strength.

A propeller thus formed may be fitted to the driving shaft b having suitable holes cut in the centre 0 the plates of the hub portion, as, for example, hexagon holes, or a. circular hole with a key-way, or key-ways.

If-required, however, a central tube may be inserted, and welded or otherwise attached to the plates, but this is not essential to my invention which admitsof the propeller bein mounted in a variety of ways. v

In or er that my invention may be clearly understood, I will describe it by reference to the accompanying drawings, in which Figure 1 is a view of a two-bladed propeller ofan ordinary design or shape, and constructed accordin to'th'e invention.

Figure 2 is a longitudinal sectional view of the same.

Figure 3 is a section on the line 33, Figure 1.

Figure 4 is "a perspectiveview of the two plates used in forming a propellerof ordinary design or shape.

Referring to the drawings which "show a two-bladed propeller, the said blades are formed from two sheet-metal plates, one of which plates forms the surface a of the two blades. and the other the surface b thereof, so that when the shaped platesare' placed together two complete blades are formed. It will be seen that each plate forms the front face of one blade and the rear face of the other blade.

c is thehubwhich is of a tubular or spoolshape and the sides of this hub are enclosed by thetwo blades a and b which are secured to it by welding, soldering, or other suitable means.

As above stated, the blades may be strengthened internally by suitablevv means, such as those described in the patent above referred to and which consists of liners with or without projecting strengthening ribs.

(2 represents pieces of thin sheet-metal with which the spaces left at the ends of the hub between the plates a and b constituting the blades, are filled in.

The hub occupies a'position in the twist of the blades like a rod passing between the strands of a double strand rope. In athre'if;

or four bladed propeller, the hub will occupy a similar position but it will be understood that each plate in the latter arrangement passes around a less portion of the hub than will be the case with a two bladed propeller.

Having now particularly described and ascertained the nature of my said invention and in What manner the same is to be per- 10 formed, I declare that what I claim is 1. A hollow metal plural bladed propeller formed of a plurality of plates, each of which is shaped to form the leading side of one blade and the trailing side of another blade.

2. A hollow metal plural bladed propeller formed of a plurality of plates, each of which is shaped to constitute the leading side of one blade and the'trailing side of another blade, the abutting edges of said 20 ether.

blades being connected to Y LEITNER.

HEN 

